Writing a Machine-Specific Lockout Procedure

A lockout procedure that says "turn off power, apply lock, verify" tells a mechanic nothing they did not already know. It does not say which of the three disconnects feeds the machine, where the air valve sits behind the guard, or that the ram must be pinned before anyone bleeds the hydraulics. OSHA's standard, 29 CFR 1910.147(c)(4), requires procedures that clearly and specifically cover how energy is controlled. Good ones are written by people who have walked the machine. As a lead or senior mechanic, you may be the one asked to write them. This covers how, and your employer's program sets the format and who approves it.

What You Will Be Able to Do

• Decide when a machine needs its own procedure and when machines can share one.
• Walk down a machine and record each energy source, its size and its isolation point.
• Write steps that a stranger could follow without guessing.
• Test a draft on the real machine.
• Keep a procedure current when the machine changes.

What the Rule Requires

The procedure must clearly and specifically lay out its scope, purpose, authorization, rules and techniques, plus how compliance is enforced. At a minimum, it includes:

Procedures only have to cover energy control. You do not need the repair steps in them, although some employers add those.

The exception. A written procedure can be skipped only when all eight conditions in the note to (c)(4)(i) are true. In short, the machine has no stored energy that could hurt anyone, it has one easily found energy source, locking that source fully shuts it down, it stays locked out during the work, one lock does it, the worker keeps sole control of that lock, the work creates no hazard for others, and the employer has had no accidents from unexpected startup on that machine. Many production machines fail on the first condition, because one air cylinder or raised part can be enough. Machines under the exception still need a lockout. They just do not need a written procedure.

One Procedure or Many

OSHA does not require a separate procedure for every machine. In its enforcement directive, CPL 02-00-147, similar machines may share a procedure if all of these are true:

• Each machine is named in the procedure's scope.
• They use the same type and size of energy.
• They have the same or similar controls.
• The same steps, in the same order, make each one safe.
• The procedure has enough detail to guide someone through each machine.

Machine-specific procedures are not required by law, but many employers choose them because they remove guesswork.

Walk Down the Machine

You cannot write this at a desk. Plan on doing it with an operator and a mechanic who know the machine, and bring the drawings. The older the machine, the less you should trust the paper.

1. Gather what exists. Get the maker's manual, electrical and fluid schematics, and any past procedure.
2. Start at the machine and trace outward. Follow each cable, hose and pipe to where it can be shut off. Do not start at the panel and assume it feeds what the label says.
3. Find every source. Check electrical power, control power, air, hydraulics, steam, water, gas, vacuum and process lines. Look at gravity, springs and rotation too.
4. Record the size of each one. Write 480 volts, 90 psi, 2,000 psi, 1,800 pounds or 350°F. The worker has to know the type and size of the energy, and "air" does not say that.
5. Find the stored energy. Mark accumulators, receivers, capacitors, raised parts and anything that coasts.
6. Choose the isolating device for each source. It must physically stop the energy. A push button, selector switch, PLC command or E-stop does not count.
7. Check that each device can take a lock. Find out what lockout hardware fits it. Since January 2, 1990, new machines, and machines getting a replacement, major repair, renovation or modification, must have devices designed to accept a lock.
8. Find how to verify. Decide which gauge, test point or try-out proves each source is dead.
9. Tag the points. Give each isolation point a unique ID and mark it on the machine, so the procedure and the plant floor use the same name.

Stop if you find a device that cannot be locked, a missing gauge, or a label you cannot trust. Those are fixes to request, not details to write around.

Put It in a Table First

An energy table gives the reader the whole picture before the steps start.

Worked example: Bundler 3 is a shrink-wrap bundler at the end of a packaging line.

That table took a walkdown to build. The drawing listed only E-1 and A-1. The walk found that control power comes from a lighting panel on the far side of the aisle, and the gate falls when the air bleeds off. A generic procedure would have missed both.

Write the Steps

Good steps read like driving directions. Follow these rules:

• One action per step. If a step says "and," look at whether it should be two.
• Start with a verb. Press, close, lock, bleed, confirm.
• Name the device and where it is. Use the ID from the table.
• Say what you should see. "Gauge PG-7 reads 0."
• Put warnings at the step where the danger is, not at the top of the page.
• Match the real order. Block before you bleed, and bring the machine to its safest position before you isolate.

Here is how the middle of the Bundler 3 procedure reads:

1. Tell the line lead and operators that Bundler 3 is going down, and why.
2. Press Cycle Stop on the HMI, and wait for the last bundle to clear.
3. Install gate pin GP-1 in the infeed gate.
4. Open disconnect DS-14 on the north wall. Lock and tag it.
5. Switch off breaker 22 in panel LP-3. Lock and tag it.
6. Close dump valve V-7 at the rear left column. Lock and tag it. Confirm that PG-7 reads 0.
7. Confirm that the tunnel display reads under 120°F before you open the tunnel.
8. Press Start on the HMI. Nothing should move. Return it to Off.
9. Have a qualified person test for voltage at the terminals listed in the drawing.

Do Not Skip the Back End

Many procedures stop at the verify step. The rule also expects steps for removing locks and transferring them. Add these:

• Return to service: inspect, reinstall guards, clear people, remove locks, notify, restart.
• Testing and positioning: when the machine can be powered up mid-job, and how to lock it back out.
• Shift change: how protection carries over if the job runs past one shift.
• Group work: who runs the lockout, and which group hardware is used.
• Contractors: who isolates, and what contractors are told.

Test the Draft

A procedure is not finished until someone uses it. Give the draft to an authorized employee who did not write it. Have them follow it on the real machine, during planned downtime, exactly as written. Stay quiet and take notes.

Watch for each moment where they hesitate, look around, or do something the page did not say. Those are the defects. Common ones include a valve that cannot be reached without a ladder, a lock that does not fit, a step that is out of order, and a gauge that cannot be seen from where it needs to be read.

Then get the review and sign-off your employer's program calls for. Put a copy where the people who use it can get to it, such as at the machine or in the maintenance system.

Keep It Current

A procedure goes stale when the machine changes and the paper does not. Review it whenever:

• A new energy source, actuator or line is added.
• A disconnect, valve or panel is moved or relabeled.
• A machine is rebuilt, retrofitted or moved to a new spot.
• A near miss, injury or failed verification shows a gap.
• The annual inspection finds that it is not adequate.

Tie this into your plant's change process so that a new air line cannot go in without someone asking, "Does this change the lockout?" Under 1910.147(c)(7)(iii), authorized and affected employees must be retrained when a change in machines or processes brings a new hazard, or when the procedure itself changes.

Why the Lock Step Cannot Be Left Out

A NIOSH investigation (FACE report 95-12) shows what a loose procedure does. At a concrete pipe plant, the cleanout routine was to shut off a breaker about 35 feet away, push a toggle switch at the mixer to confirm it was off, and climb in. No lock was part of it. An operator shut off the breaker but did not finish the routine. The worker who came to clean found the breaker off. Believing he was shutting the mixer down, he flipped it on and climbed in. When the operator came back and pushed the toggle to check, the mixer started. The worker died. Two people each did something that felt careful, and neither could see what the other had done. A lock with a name on it would have shown them.

Common Mistakes

Check Your Understanding

1. A small plant has 12 bench grinders, all cord-and-plug, and 2 larger grinders hardwired to their own disconnects. Can one procedure cover all 14?

No, because the steps differ. The two hardwired grinders are locked at their disconnects. The plug-in grinders may fall outside the standard altogether if the plug is pulled and stays under the worker's control. Treat them as two groups.

2. Your draft says, "Lock out main disconnect." The plant has four disconnects on that wall. What should you change?

Give the disconnect's ID and location, and mark the same ID on the disconnect itself.

3. During a walkdown, you find a lift table with no way to hold it up except the cylinder. What do you do?

Do not write around it. Report that a block, pin or prop is needed, and get one specified for that load before the procedure is finished.

4. A new hire follows your draft and stops at step 6 to hunt for a valve. Is that her mistake?

No. That is a defect in the procedure. Add the location, or a photo if your program uses them.

5. Maintenance adds a small air cylinder to a machine that had no stored energy. What changes?

The machine now has stored energy, so any exception from a written procedure may be gone. The procedure must be updated, and the people who use it retrained.

Key Takeaways

• A procedure must say exactly how energy is controlled on that equipment, not just repeat the general steps.
• Machines can share a procedure only if they have the same energy, same controls and same steps.
• Walk the machine, trace outward, and record each source, its size and its isolation point.
• Write one action per step, name the device, and say what the reader should see.
• Include removal, testing, shift change and group work, not only the lockout itself.
• Test each draft on the real machine, and update it when the machine changes.